Cosmetic ink composition comprising a surface tension modifier

ABSTRACT

A cosmetic ink composition comprises a particulate material, a polymeric dispersant, a rheology modifier, and a surface tension modifier, wherein the surface tension modifier is selected from the group consisting of C1-C16 alcohols, C5-C18 diols, and mixtures thereof. The particulate material can have a Particle Size Distribution D50 of about 100 nm to about 2,000 nm. The rheology modifier can be selected from the group consisting of alkali swellable emulsion polymers, hydrophobically modified alkali swellable emulsion polymers, and combinations thereof. The cosmetic ink composition can have a surface tension of from about 20 to about 45 mN/m.

FIELD OF THE INVENTION

Described herein is an ink composition for inkjet printing applications,and more particularly a cosmetic ink composition comprising aparticulate material and a surface tension modifier that can providecoverage of skin imperfections and durability on a wide range of skintypes while still being stable and suitable for high frequency printingvia thermal and/or piezo inkjet printheads.

BACKGROUND OF THE INVENTION

Most printing applications are designed for printing onto whitesubstrates for document production or photo printing. For suchapplications, black inks are primarily used in combination with three ormore colored inks. Formulating stable black inks and colored inks iswell understood. For instance, it is known that molecular dyes willgenerally not exhibit settling over time if they are soluble in thecarrier. In addition, pigment-based black inks generally utilizeparticle sizes small enough to be suspended in low viscosity carriersand take advantage of both Stokes' Law and Brownian motion to keep theparticles suspended. However, these inks exhibit very low opacity, asdyes are transparent by nature and pigmented-based black inks useparticle sizes that are small enough to be suspended but are muchsmaller than the particle sizes required to scatter visible light. Foropacifying purposes, optimal light scattering occurs at half thewavelength of light. Since the visible light spectrum ranges from about400 to about 700 nm, the optimal particle size for opacification is fromabout 200 to about 350 nm. This is significantly larger than theparticle size of stable black pigment-based inks used in consumerprinting applications which generally comprise particles that are lessthan about 50 nm in size.

For cosmetic printing applications, it is known that the ink must besufficiently opaque to cover and/or hide skin imperfections. However, itis difficult to formulate an opaque stable cosmetic ink which can bejetted due to the particle size and levels needed to achieve opacity andthe gravitational settlement of the large and/or dense particles used tocreate such inks. For many years, the inkjet printing industry hasattempted to create stable white inks that are compatible with inkjetprinter cartridges and nozzle technology. However, even the most stablecurrent white inks demonstrate particle settling over time if leftundisturbed. Manufacturers of such inks recommend vigorous shaking on adaily or weekly basis to redisperse the particles and/or recommend thatthese inks are recirculated during use.

In addition to particle suspension stability, cosmetic inks should alsobe durable on a wide range of skin types. The particles in cosmetic inksmust be deposited onto the skin and stay in place to be effective incovering skin imperfections. This is challenging because the surfaceproperties of skin can vary on a single person and fromperson-to-person. It is known that the contact angle of water on aperson's cheek can vary from 0-110 degrees due to different levels ofsebum production and/or skin care technique variation from person toperson. As a result, cosmetic inks will spread differently, dry atdifferent rates, and have varying durability on the skin, and thus willprovide varying coverage from person to person.

As such, there is a need for an opaque inkjet cosmetic ink compositionthat can be used on a wide range of skin types to hide and/or cover skinimperfections. In particular, there is a need for a cosmetic inkcomposition that comprises particles that can provide opacity and has asurface tension that will increase wettability and decrease dry time onskin, while still being stable.

SUMMARY OF THE INVENTION

A cosmetic ink composition comprises: (a) from about 1 to about 45active wt % of a particulate material having a Particle SizeDistribution D50 of about 100 nm to about 2,000 nm; (b) a rheologymodifier, wherein the rheology modifier is selected from the groupconsisting of an alkali swellable emulsion polymer, a hydrophobicallymodified alkali swellable emulsion polymer, and combinations thereof;(c) a polymeric dispersant; and (d) a surface tension modifier, whereinthe surface tension modifier is selected from the group consisting ofC1-C16 alcohols, C5-C18 diols, and mixtures thereof.

A cosmetic ink composition comprises: (a) from about 1 to about 45active wt % of a particulate material; (b) greater than about 0.30active wt % of a rheology modifier, wherein the rheology modifier isselected from the group consisting of a (meth)acrylate polymer, a(meth)acrylate copolymer, and mixtures thereof; (c) from about 0.01 toabout 1 active wt % of a polymeric dispersant; (d) from about 0.1 toabout 5 active wt % of a surface tension modifier, wherein the surfacetension modifier is selected from the group consisting of C1-C16alcohols, C5-C18 diols, and mixtures thereof; and (e) from about 10 toabout 30 active wt % of a humectant.

A cosmetic ink composition comprises: (a) a particulate materialcomprising titanium dioxide; (b) a rheology modifier, wherein therheology modifier is selected from the group consisting of a(meth)acrylate polymer, a (meth)acrylate copolymer, and mixturesthereof; (c) a polymeric dispersant; and (d) from about 0.1 to about 5active wt % of a surface tension modifier, wherein the surface tensionmodifier is selected from the group consisting of C1-C16 alcohols,C5-C18 diols, and mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed the samewill be better understood from the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 is an exploded view of a personal care device for use indepositing the cosmetic ink composition described herein; and

FIG. 2 is an exploded view of a cartridge containing the cosmetic inkcomposition described herein.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, “active wt %” and “wt % (active)” refers to the amountof solid of an ingredient dissolved or suspended in water in thecomposition.

As used herein, “ambient conditions” refers to a temperature of about 23degrees Celsius (° C.) and 50% relative humidity (RH).

As used herein, “durable” refers to a property of the composition thatdescribes the ability to dry quickly and withstand wear on skin.

As used herein, “Particle Size Distribution D50” refers to the diameterwhere fifty percent of the distribution has a smaller particle size.

As used herein, “Particle Size Distribution D90” refers to the diameterwhere ninety percent of the distribution has a smaller particle size.

As used herein, “separation” refers to the formation of a clear fluidlayer at the top of a sample regardless of the uniformity of theparticles in the sample below the clear fluid layer. Separation caninclude particle settling and/or syneresis.

As used herein, “settling” refers to the falling of particles in acomposition due to gravity (according to Stokes' Law) to the bottom of acontainer. Particle settling can be affected by the size of theparticles and their agglomeration over time.

As used herein, “static storage” refers to storage of a composition inthe absence of vigorous or sustained vibration, agitation, or mixingprior to analysis or deposition of the composition.

As used herein, “syneresis” means phase separation, i.e. extraction orexpulsion of a liquid from a gel, in this case a weak colloidal gel. Theparticles in a composition exhibiting syneresis are still uniformlysuspended below the clear fluid layer.

As used herein, “ratio of polymeric dispersant to rheology modifier”refers to the ratio of the active wt % of the polymeric dispersantdivided by the active wt % of the rheology modifier.

As used herein, “the storage modulus” or “G′” refers to the measure ofthe stored energy, representing the elastic portion of the composition.

As used herein, “the loss modulus” or “G″” refers to the measure of theenergy dissipated as heat, representing the viscous portion of thecomposition.

As used herein, “weight percent as added” refers to the amount of thetotal active plus water as added to the composition.

As used herein, “zeta potential” refers to the electrokinetic potentialof the cosmetic ink composition.

As used herein, the articles “a” and “an” are understood to mean one ormore of the material that is claimed or described, for example, “arheology modifier” or “an active”.

All weights, measurements and concentrations herein are measured atambient conditions unless otherwise specified.

All percentages, parts, and ratios as used herein are based upon thetotal weight of the cosmetic ink composition, unless otherwisespecified. All such weights as they pertain to listed ingredients arebased on the level as added in the composition, unless otherwisespecified.

Cosmetic inks can require a white or light colored particulate materialcomprising particles large enough to be visually perceptible to thehuman eye in order to create opacity to cover skin imperfections.However, printing a cosmetic ink composition comprising a particulatematerial having a particle size large enough to be visually perceptiblecan be a challenge for current inks, printers, and/or cartridges. Thesechallenges are caused primarily by the settling of the large, denseparticles and secondarily by the packing of the settled particles in thecartridge. Re-mixing, either by automated mixing or hand shaking, maynot be compatible with consumer in-home or hand-held printing purposesbecause of the vigorous and repeated re-mixing needed to keep theparticles uniformly suspended.

In addition, cosmetic inks should be able to spread on the skin toprovide sufficient coverage of skin imperfections and be durable on awide variety of skin types. However, this can be difficult because ofthe variability in the surface properties of the skin. If the surfacetension of the cosmetic ink is too high, the cosmetic ink can bead-up onthe skin and not properly spread, impacting the ability of the cosmeticink to cover skin imperfections. Surprisingly, it was found that theinclusion of certain surface tension modifiers in the cosmetic inkcomposition can improve the coverage and durability on skin withoutlowering viscosity and disrupting particle suspension stability. Inparticular, it was found that a cosmetic ink composition comprising aparticulate material, such as TiO₂, a rheology modifier selected fromthe group consisting of alkali swellable emulsion (“ASE”) polymers,hydrophobically modified alkali swellable emulsion (“HASE”) polymers,and combinations thereof, a polymeric dispersant, and a surface tensionmodifier selected from the group consisting of C1-C16 alcohols, C5-C18diols, and mixtures thereof, can provide coverage and durability on arange of skin types while maintaining viscosity and long-term particlesuspension stability. Also described herein is a personal care devicefor depositing the cosmetic ink composition.

Cosmetic Ink Composition

The cosmetic ink composition can comprise a particulate material,rheology modifier, a polymeric dispersant, and a surface tensionmodifier. Without being limited by theory, it is believed that thesurface tension modifier can lower the surface tension of the cosmeticink composition such that the cosmetic ink composition is capable ofwetting a wide range of skin types without lowering the viscosity of thecomposition, which can disrupt the suspension of the particles.

It was also found that balancing of the agglomeration of the particlesand viscosity of the cosmetic ink composition can be used to inhibitparticle settling, providing particle suspension stability beyond whichhas been previously reported without hindering high frequency printingcapabilities via thermal and/or piezo inkjet printheads. One advantageto this is that little to no shaking, and/or agitation of the cosmeticink composition by the consumer or automated mechanical processes beforeand/or during printing is needed to re-disperse the particles. This canmake the cosmetic ink composition more user-friendly as it does notrequire the consumer to perform an additional step to re-disperse theparticles and/or can eliminate the need for agitation or rotationsystems, including automated systems, within the printing device,cartridge, printer servicing station, and/or docking station. In oneaspect, the cosmetic ink composition need not be agitated or shaken tore-disperse the particles before and/or during use because the particlescan remain in suspension over the shelf-life of the product.

Without being limited by theory, it is believed that the cosmetic inkcomposition can be stabilized using a polymeric dispersant to minimizeand/or prevent particle agglomeration and a rheology modifier tointroduce a secondary structure and build viscosity to suspend theparticles in a weak colloidal gel. The colloidal gel can be strongenough to hold the particles in suspension when not printing (thusinhibiting particle settling), but weak enough to break up duringprinting. Without being limited by theory, it is believed that theamphilicity of the hydroxyl group(s) and alkyl chains of the surfacetension modifier can impart some surface activity without significantlydisrupting the colloidal gel.

In one aspect, the cosmetic ink composition can be a skin carecomposition. The cosmetic ink composition can hide or camouflage a skinimperfection, such as hyperpigmentation, when deposited precisely andsubstantially only onto the skin imperfection.

In one aspect, the cosmetic ink composition can be jetted onto anysurface, preferably a keratinous surface including human skin and/orhair.

The cosmetic ink composition can be non-Newtonian, meaning the cosmeticink composition can have a shear dependent viscosity and/or viscoelasticproperties. The cosmetic ink composition can show shear thinning effectsunder the fluid ejection conditions in which the ink is moved betweenthe cartridge and the printhead of an inkjet device. When the cosmeticink composition is jetted, the shear rate can increase, resulting in adecrease in the viscosity. Thus, the cosmetic ink composition can bestored without particle settling, yet the viscosity and particle sizeare such that the cosmetic ink composition can still be printed.

In one aspect, the particulate material can be hydrophilic. Theparticulate material can be substantially coated with one or moreingredients to cause the particulate material to become morehydrophilic. As used herein, “substantially coated” can mean at leastabout 25%, preferably greater than about 50%, surface coverage of theparticulate material, more preferably greater than about 75%, mostpreferably greater than about 90%. Suitable coating ingredients that canrender the particulate material hydrophilic in nature can includesilica, alumina, polyethylene glycol (PEG) 12 dimethicone, phytic acid,sodium glycerophosphate, and combinations thereof. The particulatematerial can be substantially coated with one or more coatingingredients using techniques known in the art. One advantage to using ahydrophilic particulate material is that hydrophilic particulatematerial can be more easily dispersed in water. In one aspect, theparticulate material can be titanium and/or iron oxide which has beensubstantially coated with silica and/or alumina.

Suitable particulate materials can include pigments; encapsulatedpigments; mica; clay; mixed metal oxide pigments; metal oxides such asiron oxide, titanium dioxide, zinc oxide, aluminum hydroxide, ironoxide, and combinations thereof; boron nitride; silica; talc; basic leadcarbonate; magnesium silicate; baryte (BaSO₄); calcium carbonate;pearlescent; colorants, including natural colorants and syntheticmonomeric and polymeric colorants; dyes such as azo, indigoid,triphenylmethane, anthraquinone, and xanthine dyes which are designatedas D&C and FD&C blues, browns, greens, oranges, reds, yellows, etc.;insoluble metallic salts of certified color additives, referred to asthe Lakes; and combinations thereof.

In one aspect, the particulate material can comprise titanium dioxide,iron oxide, and combinations thereof. In one aspect, the titaniumdioxide and/or iron oxide can be readily dispersed in water. In oneaspect, the titanium dioxide and/or iron oxide is not hydrophobicallytreated before use in the cosmetic ink composition because it may not bereadily dispersed in water. Suitable particulate material can includeslurries of titanium dioxide and iron oxide available from KOBO ProductsInc (South Plainfield, N.J.), or equivalents.

In one aspect, the cosmetic ink composition comprises a white pigment.

In one aspect, the cosmetic ink composition can have a white appearance.Alternatively, the cosmetic ink composition can have a white appearancewith tints of red and/or yellow.

Typical levels of particulate material for sufficient opacity to hideand/or camouflage skin imperfections can be around 30 active wt %. Inone aspect, the cosmetic ink composition can comprise greater than about15 active wt % particulate material, alternatively greater than about 20active wt %, alternatively greater than about 30 active wt %. In oneaspect, the cosmetic ink composition can comprise from about 1 to about45 active wt % particulate material, alternatively from about 3 to about30 active wt %, alternatively from about 5 to about 25 active wt %,alternatively from about 8 to about 18 active wt %.

The particulate material can comprise particles having a Particle SizeDistribution (PSD) D50 of about 100 nm to about 2,000 nm, alternativelyfrom about 150 nm to about 1,000 nm, alternatively from about 200 nm toabout 450 nm, alternatively from about 200 nm to about 350 nm. In oneaspect, the particulate material can comprise particles having a PSD D90of less than about 2 μm, alternatively less than about 1 μm. In oneaspect, the particulate material can comprise particles having a PSD D90of from about 700 to about 900 μm. Without being limited by theory, itis believed that if the particles are too big, they can clog themicrofluidic channels of the cartridge and disrupt printing. One skilledin the art would understand that an acceptable particle size can varydepending on printhead die architecture. In one aspect, the particulatematerial can comprise any PSD so long as the particles can move throughthe microfluidic channels of the cartridge and/or the printhead withoutcausing clogging. The Particle Size Distribution can be measuredaccording to the Particle Size Distribution Method described hereafter.

The particulate material can have a refractive index of between about1.1 and about 5.0, alternatively from about 1.5 to about 4,alternatively from about 2 to about 3.

The particulate material can have a density range of from about 1.5 toabout 6 g/mL, alternatively from about 2 to about 4 g/mL.

The cosmetic ink composition can comprise a rheology modifier. Rheologymodifiers can assist in preventing settling by keeping the particlesuniformly suspended such that little to no agitation of the cosmetic inkcomposition is needed.

One preferred group of rheology modifiers are ASE polymers. ASE polymerscontain a balance of hydrophilic (meth)acrylic acid monomers andhydrophobic (meth)acrylate ester monomers and can be supplied at highvolume solids in liquid form. ASE polymers rely on a change from low tohigh pH (neutralization) to trigger thickening. The “trigger” is builtinto the polymer by creating an approximately 50:50 ratio of(meth)acrylic acid, which is soluble in water, and a (meth)acrylateester, which is not soluble in water. When the acid is un-neutralized(low pH), the polymer is insoluble in water and does not thicken. Whenthe acid is fully neutralized (high pH), the polymer becomes soluble andthickens. ASE polymers are supplied at low pH (<5) and maintain a lowas-supplied viscosity (<100 cP) at solids of up to 35%. When subject toa pH of about 7 or higher, ASE polymers solubilize, swell, and thickenthe composition through volume exclusion. The degree of thickening canbe related to the molecular weight of the polymer. Because theirperformance depends on water absorption and swelling, ASE polymers tendto be very high in molecular weight, which allows them to thickenefficiently. The rheology profiles ASE polymers create are typicallysteeply shear-thinning (pseudoplastic), and thus ASE polymers are wellsuited to build high viscosity at very low shear rates. Differentrheological characteristics can be achieved by manipulating themolecular weight, as well as the types and amounts of acid and estermonomers, of the polymer.

In one aspect, the hydrophilic monomers of the ASE polymer can include(meth)acrylic acid and maleic acid. In one aspect, the hydrophobicmonomers of the ASE polymer can include the esters of (meth)acrylic acidwith C₁- to C₄-alcohols, in particular ethyl acrylate, butyl acrylate,and methyl methacrylate.

In one aspect, the ASE polymer can be synthesized from 10-90 wt % ofHydrophilic Monomer A and 10-90 wt % of Hydrophobic Monomer B. Thestructure of Hydrophilic Monomer A and Hydrophobic Monomer B are shownbelow.

wherein R₁ and R₂ are independently hydrogen or methyl;

-   -   wherein R₃ is C₁ to C₄ alkyl.

Yet another group of rheology modifier suitable for use in the cosmeticink composition described herein are HASE polymers. These are tertiarypolymers that build on the ASE polymer chemistry by adding a hydrophobicacrylic ester and/or vinyl ester monomer to the polymer composition.HASE polymers retain the pH dependent behavior of their ASEcounterparts, but in addition to absorbing water, HASE polymers alsothicken via hydrophobe association. This mechanism, known as associativethickening (i.e. associating with any hydrophobic moiety in thecomposition), offers performance properties over a wider range of shearlevels and enables a wider range of rheology profiles than is possiblewith volume exclusion thickeners such as ASE and cellulosiccompositions.

The hydrophilic and hydrophobic monomers of the HASE polymers can be thesame as described with respect to the ASE polymers. The associativemonomer of the HASE polymer can be a monomer that shows a stronghydrophobic character. A preferred associative monomer is ester of(meth)acrylic acid with C₈-C₂₂ alcohols.

In one aspect, the HASE polymer can be synthesized from 10-90 wt %Hydrophilic Monomer A, 10-90 wt % Hydrophobic Monomer B, and 0.01 to 2wt % Associative Monomer C. The structure of Associate Monomer C isshown below.

wherein R₄ is hydrogen or methyl;wherein R₅ is C₈ to C₂₂ alkyl;wherein n is an integer from 0 to 50.

Alternatively, the HASE polymer can be synthesized from 10-90 wt %Hydrophilic Monomer A, 10-90 wt % Hydrophobic Monomer B, and 0.01 to 2wt % Associative Monomer D. The structure of Associative Monomer D isshown below.

wherein R₆ is hydrogen or methyl;wherein R₇ is C₈ to C₂₂ alkyl.

In one aspect, the associative monomer can be selected from the groupconsisting of steareth-20 methacrylate, beheneth-25 methacrylate, vinylneodecanoate, and combinations thereof. In one aspect, more than oneassociative monomers can be used in the synthesis of the HASE polymer.

In one aspect, ASE and HASE polymers can comprise a cross-linking agent.The cross-linking agent can contain at least two ethylenicallyunsaturated moieties, alternatively at least three ethylenicallyunsaturated moieties. Suitable cross-linking agents can include divinylbenzene, tetra allyl ammonium chloride, allyl acrylates, methacrylates,diacrylates, dimethacrylates of glycols and polyglycols, butadiene,1,7-octadiene, allyl-acrylamides, allyl-methacrylamides,bisacrylamidoacetic acid, N,N′-methylene-bisacrylamide, polyolpolyallylethers such as polyallylsaccharose and pentaerythroltriallylether, and mixtures thereof. The cross-linking agent can bepresent at a level of from about 25 to about 5,000 ppm, alternativelyfrom about 50 to about 1,000 ppm, alternatively from about 100 to about500 ppm.

Another group of rheology modifiers are hydrophobically-modifiedethylene oxide-based urethane (HEUR) polymers. Unlike ASE or HASE-typerheology modifiers, HEUR polymers are non-ionic and soluble at any pH.This solubility is due to the polymer's ethylene oxide backbone, whichis water soluble and makes up the majority of the polymer structure.Thus, HEUR polymers require a hydrophobic moiety in the composition tointeract with the ethylene oxide backbone to impart structure. Thecosmetic ink composition can comprise a HEUR polymer. Alternatively, thecosmetic ink composition comprises little to no hydrophobic moieties anddoes not comprise a HEUR polymer.

The rheology modifier can be a (meth)acrylate polymer, a (meth)acrylatecopolymer, and mixtures thereof. The rheology modifier can be selectedfrom the group consisting of ASE polymers, HASE polymers, andcombinations thereof. Suitable HASE polymers can include ACULYN™ Excel;ACRYSOL™ TT615; ACULYN™ 22; ACULYN™ 88; (all available from The DOWChemical Company, Lake Zurich, Ill.); and combinations thereof. SuitableASE polymers can include Rheovis® 1125 (available from BASF Corporation,Charlotte, N.C.), ACULYN™ 33; ACULYN™ 38 (both available from The DOWChemical Company, Lake Zurich, Ill.); and combinations thereof. Thecosmetic ink composition can comprise an ASE polymer. Alternatively, thecosmetic ink composition can comprise an HASE polymer.

The rheology modifier does not consist of a surfactant, an amine oxide,and/or a cellulosic ether.

The cosmetic ink composition can comprise any amount of rheologymodifier so long as the first dynamic viscosity of the cosmetic inkcomposition is greater than about 500 cP at a shear rate of 0.1 sec⁻¹measured at 25° C., preferably greater than about 1,100 cP at a shearrate of 0.1 sec⁻¹ measured at 25° C. The cosmetic ink composition cancomprise greater than about 0.30 active wt % rheology modifier,alternatively greater than about 0.40 active wt %, alternatively greaterthan about 0.50 active wt %. The cosmetic ink composition can comprisefrom about 0.30 to about 1 active wt % rheology modifier, alternativelyfrom about 0.30 to about 0.80 active wt %, alternatively from about 0.40to about 0.50 active wt %. Active wt % can be measured using standardHigh Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS)techniques. One advantage to keeping the level of rheology modifierwithin this range is that the viscosity of the cosmetic ink compositioncan be built such that the particles can be suspended in thecomposition. The particles can be suspended for about 11 days or more at25° C., alternatively about 30 days or more at 25° C., alternatively forabout 90 days or more at 25° C., alternatively for about 300 days ormore at 25° C. Without being limited by theory, it is believed that atlevels of rheology modifier below this range, the particles may not besufficiently suspended and settling may occur. If the level of rheologymodifier is too high, the viscosity of the cosmetic ink composition mayincrease to a point that can impact jetting (i.e. the cosmetic inkcomposition may not shear thin enough for efficient printing).

In one aspect, the cosmetic ink composition can be substantially free ofneutral inorganic salts (as compared to an alkali salt base, like NaOH).Without being limited by theory, it is believed that neutral inorganicsalts, such as calcium chloride or sodium chloride, can increase theionic strength of the cosmetic ink composition and can disrupt theinternal structure, thus impacting stability. It is known that HASEand/or ASE polymers become polyelectrolytes at high pHs. As pHincreases, the carboxylic acids on the HASE and/or ASE polymers can beneutralized, generating ionic groups on the polymer chains that canproduce electrostatic repulsion. These electrostatic repulsions cancause the polymer to expand and form an internal structure in thecomposition. It is believed that inorganic neutral salts can shield thiselectrostatic repulsion and can cause the HASE and/or ASE polymer tochange structure, and thus its effectiveness in promoting stability.

The cosmetic ink composition comprises a polymeric dispersant. Thepolymeric dispersant can be a low molecular weight linear or branchedhomopolymer or copolymer that can act to control particle size and canhelp maintain a low viscosity in the cosmetic ink composition. Thepolymeric dispersant does not greatly increase viscosity of the cosmeticink composition. Examples of polymeric dispersants that can be usedherein can include polymers obtained from one or more hydrophilicmonomers and optionally hydrophobic monomers.

Non-limiting examples of hydrophilic monomers can include styrenesulfonic acid; ALPHA, BETA-ethylenically unsaturated carbonic acid;derivatives of ALPHA, BETA-ethylenically unsaturated carbonic acid;acrylic acid; derivatives of acrylic acid; methacrylic acid; derivativesof methacrylic acid; maleic acid; derivatives of maleic acid; itaconicacid; derivatives of itaconic acid; fumaric acid; derivatives of fumaricacid; and combinations thereof.

Non-limiting examples of hydrophobic monomers can include styrene;derivatives of styrene; vinyltoluene; derivatives of vinyltoluene;vinylnaphthalene; derivatives of vinylnaphthalene; butadiene;derivatives of butadiene; isoprene; derivatives of isoprene; ethylene;derivatives of ethylene; propylene; derivatives of propylene; alkylesters of acrylic acid; alkyl esters of methacrylic acid; andcombinations thereof.

The polymeric dispersant may also comprise a monomer selected from thegroup consisting of a polyoxyethylene group, a hydroxyl group,acrylamide, acrylamide derivatives, dimethylaminoethyl methacrylate,ethoxyethyl methacrylate, butoxyethyl methacrylate, ethoxytriethylenemethacrylate, methoxypolyethyleneglycol methacrylate, vinylpyrrolidone,vinylpyridine, vinylalcohol, alkylethers any salts thereof, andcombinations thereof.

The polymeric dispersant may be in the acid form. The polymericdispersant can be a salt of the acid form. Non-limiting examples ofsalts can include onium compounds of hydrogen, alkali metals, ammoniumion, organic ammonium ion, phosphonium ion, sulfonium ion, oxonium ion,stibonium ion, stannonium ion, iodonium ion, other onium ions, andcombinations thereof.

In one aspect, the polymeric dispersant can be a polyacrylic acid or asalt thereof, such as sodium, potassium, ammonium, and mixtures thereof.In one aspect, the polymeric dispersant can be sodium polyacrylate suchas Darvan® 811D (available from RT Vanderbilt Holding Company Inc.,Norwalk, Conn.), ammonium polyacrylate having a weight average molecularweight of about 3,500 daltons such as Darvan® 821A (available from RTVanderbilt Holding Company Inc.), and combinations thereof.

The polymeric dispersant can have a weight average molecular weight ofless than about 20,000 daltons, preferably less than about 10,000daltons, more preferably less than about 5,000 daltons. The cosmetic inkcomposition can comprise a polymeric dispersant having a weight averagemolecular weight of from about 1,000 to about 20,000 daltons,alternatively from about 1,000 to about 10,000 daltons, alternativelyfrom about 2,000 to about 5,000 daltons, alternatively from about 2,500to about 4,000 daltons. Weight average molecular weight can be measuredby standard High Performance Size-Exclusion Chromatography per ASTMmethod D5296-11 (Sep. 1, 2011).

In one aspect, the polymeric dispersant is not a film forming polymer.Without being limited by theory it is believed that the polymericdispersant will not form a film because of the low molecular weight.

The cosmetic ink composition can comprise from about 0.01 to about 1active wt % polymeric dispersant, alternatively from about 0.10 to about0.85 active wt %, alternatively from about 0.20 to about 0.75 active wt%, alternatively about 0.30 to about 0.65 active wt %. Without beinglimited by theory, it is believed that the polymeric dispersant cancontrol agglomeration, and thus the particle size, of the particulatematerial by creating a negative surface charge around the particles.Thus, the polymeric dispersant can help to maintain a particle size thatis compatible with printer cartridges and nozzles. Without being limitedby theory, it is believed that a cosmetic ink composition comprisingbelow 0.01 active wt % polymeric dispersant may not have sufficientparticle size control and/or the viscoelastic modulus may be too high toallow for reliable refill of the microfluidics.

The ratio of the polymeric dispersant to the rheology modifier can beless than about 1. The ratio of polymeric dispersant to rheologymodifier can be from about 0.10 to about 0.75, alternatively from about0.30 to about 0.65. Without being limited by theory it is believed thatif the level of polymeric dispersant is greater than the level ofrheology modifier, the rheology modifier may not be able to build theinternal structure needed to suspend the particles. If the ratio ofpolymeric dispersant to rheology modifier is too low, agglomeration maynot be well controlled and the particle size may become too large to fitthrough printer nozzles, making printing difficult.

It is believed that stability is inversely proportional to the level ofpolymeric dispersant and directly proportional to the level of rheologymodifier.

The cosmetic ink composition can comprise a surface tension modifier. Inone aspect, the surface tension modifier can be a C1-C16 alcohol, aC5-C18 diol, and combinations thereof. As used herein, “C1-C16 alcohol”refers to nonionic molecules comprising one hydroxyl group, from about 1to about 16 carbon atoms, and further comprising only carbon, hydrogen,halogen, and/or oxygen atoms. As used herein, “C5-C18 diol” refers tononionic molecules comprising two hydroxyl groups, from about five toabout 18 carbon atoms, and further comprising of only carbon, hydrogen,and/or oxygen atoms. The C1-C16 alcohols and/or C5-C18 diols may besaturated, unsaturated, linear, cyclic and/or branched. In one aspect,the C1-C16 alcohols and/or C5-C18 diols can be free of carboxylic acidsmoieties.

Non-limiting examples of C1-C16 alcohol surface tension modifiers caninclude methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol,2-methyl-1-propanol, 2-methyl-2-propanol, farnesol, benzyl alcohol,phenyl ethyl alcohol, phenoxyethanol, 2-phenylphenol, methyl4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate,butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, chloroxylenol,2-methyl 5-cyclohexypentanol, triclosan, and combinations thereof.

Non-limiting examples of C5-C18 diol surface tension modifiers caninclude 1,2-pentanediol, 1,2-hexanediol, 1,6-hexanediol,2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2-methyl5-cyclohexypentanol, 1,2-decanediol,3-[(2-Ethylhexyl)oxy]-1,2-propanediol and mixtures thereof.

In one aspect, the surface tension modifier can comprise a C6-C12alcohol. In one aspect, the surface tension modifier can comprise amixture of 1,2-Hexanediol and 1,2-Octanediol (commercially available asSymDiol® 68 from Symrise, AG, Branchburg, N.J.). In one aspect, thesurface tension modifier can comprise a C15 alcohol, such as Farnesol(commercially available from Symrise AG, Branchburg, N.J.). In oneaspect, the surface tension modifier can comprise ethanol.

The cosmetic ink composition can comprise from about 0.1 to about 5active wt % of a surface tension modifier, alternatively from about 0.50to about 3 active wt %, alternatively from about 1 to about 2 active wt%. Alternatively, the cosmetic ink composition can comprise from about0.005 to about 3 active wt % of a surface tension modifier.

One advantage to including such a surface tension modifier in thecosmetic ink composition is that it can lower the surface tension whilemaintaining the viscosity and stability of the cosmetic ink. Anotheradvantage is that it can provide preservative benefits. A preservativecan help to prevent microbial growth in the cosmetic ink composition,for instance if the cosmetic ink composition becomes contaminated withbacteria from the skin.

Surfactants, such as alkyl amine oxides, are known to reduce surfacetension of aqueous compositions. Without being limited by theory, it isbelieved that in the cosmetic ink composition described herein,surfactants can interact with the particulate material, rheologymodifier, and/or polymeric dispersant in a way that can reduceviscosity, and consequently, reduce the particle suspension stability ofthe cosmetic ink formulation. Additionally, some surfactants can beirritating to the skin and unacceptable for skin care use.

The cosmetic ink composition can have a surface tension of from about 20mN/m to about 45 mN/m, alternatively from about 30 mN/m to about 40mN/m. It was found that if the surface tension of the cosmetic inkcomposition is above 45 mN/m, the cosmetic ink composition can bead-upon some skin types and may not provide acceptable wetting and/ordurability. If the cosmetic ink composition beads-up too much on theskin, the drops can shrink in size when they dry, impacting the dropletdeposition pattern and the ability of the cosmetic ink composition tocover skin imperfections. In addition, beading of the cosmetic inkcomposition on the skin can increase the drying rate, which can causesmearing if the user does not wait long enough for the composition todry before touching it. It was found that if the surface tension of thecosmetic ink composition is below 20 mN/m, it may be difficult to printthe cosmetic ink composition because it can be harder to refill thechamber through capillary action. In addition, as the surface tensiondecreases, the Rayleigh instability can increase, resulting in anincrease in drop placement error and a decrease in drop placementprecision.

The cosmetic ink composition can have a first dynamic viscosity ofgreater than about 500 cP at a shear rate of 0.1 sec⁻¹ measured at 25°C. and a second dynamic viscosity of less than about 100 cP at a shearrate of 1,000 sec⁻¹ measured at 25° C. The cosmetic ink composition canhave a first dynamic viscosity of from about 500 cP to about 10,000 cPat a shear rate of 0.1 sec⁻¹ at 25° C., alternatively from about 1,100cP to about 8,000 cP, alternatively from about 1,600 cP to about 6,000cP, alternatively from about 2,000 cP to about 5,000 cP. The cosmeticink composition can have a second dynamic viscosity of from about 10 cPto about 100 cP at a shear rate of 1,000 sec⁻¹ at 25° C., alternativelyfrom about 20 to about 80 cP. Viscosity can be measured according to theViscosity Test Method described hereinafter. One advantage to having afirst and second dynamic viscosity in this range is that at high shearrate, the cosmetic ink composition can drop to a viscosity that issimilar to Newtonian inks, yet can still maintain a viscosity sufficientto suspend the particles when not printing.

Without being limited by theory, it is believed that a shear rate of 0.1sec⁻¹ can be representative of storage conditions, while a shear rate of1,000 sec⁻¹ can be representative of printing conditions.

The cosmetic ink composition can have a first dynamic viscosity measuredat a shear rate of 0.1 sec⁻¹ at 25° C. that is about 70% higher than thesecond dynamic viscosity of the cosmetic ink composition when measuredat a shear rate of 1,000 sec⁻¹ at 25° C., alternatively about 80%higher, alternatively about 90% higher, alternatively about 95% higher.The cosmetic ink composition can have a first dynamic viscosity measuredat a shear rate of 0.1 sec⁻¹ at 25° C. that is about 25 times greaterthan the second dynamic viscosity of the cosmetic ink composition whenmeasured at a shear rate of 1,000 sec⁻¹ at 25° C., alternatively about35 times greater, alternatively about 50 times greater, alternativelyabout 80 times greater.

The cosmetic ink composition can have temperature dependent viscosity.Lower viscosity was observed at a shear rate of 1000 sec⁻¹ at anelevated temperature of about 70° C.

The cosmetic ink composition can have a storage modulus (G′) of fromabout 2 to about 10, alternatively from about 3 to about 8,alternatively from about 4 to about 6. Without being limited by theory,it is believed that if the G′ of the cosmetic ink composition is greaterthan about 10, the decap or start up after idle time in the printheadmay be difficult without intervention because the composition is tooelastic. Storage modulus can be measured according to the OscillatoryStrain Sweep Method described hereafter.

The cosmetic ink composition can have a loss modulus (G″) of from about1 to about 5, alternatively from about 1.8 to about 4, alternativelyfrom about 2 to about 3. Loss modulus can be measured according to theOscillatory Strain Sweep Method described hereafter.

The ratio of loss modulus to storage modulus, or tan(delta), is a usefulrepresentation of the extent of elasticity in a fluid. In this case, itcan be a measure of the intrinsic stability of the cosmetic inkcomposition. When G″ is higher than G′, tan(delta) is greater than about1 and indicates a viscous dominant fluid behavior. When G′ is higherthan G″, tan(delta) is less than about 1 and indicates an elasticdominant fluid behavior.

The cosmetic ink composition can have a tan(delta) of about 1.Alternatively, the cosmetic ink composition can have a tan(delta) ofless than about 1, preferably less than about 0.6. Without being limitedby theory it is believed that when the tan(delta) is less than about0.6, particle settling can be minimized and/or prevented. The cosmeticink composition can have a tan(delta) of from about 0.2 to about 1,alternatively from about 0.4 to about 0.6.

The cosmetic ink composition can have a zeta potential of about negative20 or less, alternatively about negative 30 or less, alternativelygreater than about positive 20, alternatively greater than aboutpositive 30. The cosmetic ink composition can have a zeta potential ofabout negative 20 or less, or greater than about positive 20. Oneadvantage to having a zeta potential in this range is that the surfacecharge of the particles can be increased, thus preventing agglomerationof the particles. Zeta potential can be measured according to the ZetaPotential Test Method described hereafter.

The cosmetic ink composition can have a neat pH of greater than about7.5. The cosmetic ink composition can have a neat pH of about 7.5 toabout 9.0, alternatively from about 7.5 to about 8.5. Without beinglimited by theory, it is believed that at a pH lower than about 7.5,syneresis can occur at a faster rate. It is believed that at a lower pH,the equilibrium between the carboxylic acid and carboxylate salts of therheology modifier can be pushed toward the protonated acid and thereforeare not available to suspend the particles. It is believed that as thepH increases, the larger the negative zeta potential becomes, thuspreventing agglomeration of the particles. The cosmetic ink compositioncan comprise a buffering agent for adjusting the pH conditions. Thebuffering agent can be any basic excipient. In one aspect, the bufferingagent can be a strong base, such as sodium hydroxide, potassiumhydroxide, calcium hydroxide, and mixtures thereof. The neat pH of thecosmetic ink composition can be measured by standard methodology knownto those skilled in the art.

The cosmetic ink composition can have an opacity of at least 0.2. In oneaspect, the cosmetic ink composition can comprise an opacity of fromabout 0.2 to about 1, alternatively from about 0.25 to about 0.8,alternatively from about 0.3 to about 0.5.

The cosmetic ink composition can be substantially free of particlesettling. Substantially free of particle settling can mean that thevariation between the weight % solids of the top and bottom of a sampleof the cosmetic ink composition is less than 5% at ambient conditions at4 days after formulation, alternatively less than about 3%,alternatively less than about 1%. Particle settling can be measuredaccording to the Particle Settling Test Method described hereafter.

The cosmetic ink composition can be substantially free of particleagglomeration. Substantially free of particle agglomeration can meanthat the cosmetic ink composition exhibits less than about 25 nm ofparticle growth per month at ambient conditions, alternatively less thanabout 15 nm, alternatively less than about 10 nm. The rate ofagglomeration can be determined by measuring particle size according tothe Particle Size Distribution method described hereafter over a periodof time.

The cosmetic ink composition can have less than about 10% separation at11 days after formulation at 25° C., alternatively less than about 5%,alternatively less than about 2%, alternatively less than about 1%. Inone aspect, the cosmetic ink composition can have less than about 4 mmof separation at 11 days after formulation at 25° C., alternatively lessthan about 2 mm, alternatively less than about 1 mm, alternatively lessthan about 0.50 mm. Separation can be measured according to theSeparation Test Method described hereafter.

The cosmetic ink composition can have a shelf-life of about 1 month,alternatively about 3 months, alternatively about 6 months,alternatively about 12 months, alternatively about 18 months,alternatively about 24 months. As used herein, “shelf-life” means theamount of time the particles can remain uniformly suspended in thecosmetic ink composition at ambient conditions without the need forshaking or agitation.

The cosmetic ink compositions may further comprise a humectant as acarrier or chassis for the other components in the cosmetic inkcomposition. In one aspect, suitable humectants can include polyalkyleneglycols and their derivatives. In one aspect, an exemplary class ofhumectants can include polyhydric alcohols with three or more hydroxylgroups. Suitable polyhydric alcohols can include propylene glycol;sorbitol; hydroxypropyl sorbitol; erythritol; threitol; pentaerythritol;xylitol; glucitol; mannitol; hexane triol (e.g., 1,2,6-hexanetriol);glycerin; ethoxylated glycerine; propoxylated glycerine; and mixturesthereof. In one aspect, the humectant is propylene glycol.

Other suitable humectants can include sodium2-pyrrolidone-5-carboxylate; guanidine; glycolic acid and glycolatesalts (e.g., ammonium and quaternary alkyl ammonium); lactic acid andlactate salts (e.g., ammonium and quaternary alkyl ammonium); hyaluronicacid and derivatives thereof (e.g., salt derivatives such as sodiumhyaluronate); urea; sodium pyroglutamate, water-soluble glycerylpoly(meth)acrylate lubricants (such as Hispagel®, available from BASF,Ludwigshafen, Germany); and mixtures thereof.

The cosmetic ink composition can comprise from about 1 to about 40active wt % humectant, alternatively from about 5 to about 35 active wt%, alternatively from about 10 to about 30 active wt %, alternativelyfrom about 15 to about 25 active wt %. Alternatively, the cosmetic inkcomposition can comprise from about 20 to about 30 active wt %humectant.

Without being limited by theory, it is believed that at a level of about20 active wt % or more, the humectant can help prevent drying and/orclogging of the nozzles and/or cartridge when the cosmetic inkcomposition is not being printed. In one aspect, the level of humectantis less than about 30 active wt % to promote fast dry times of thecosmetic ink composition on the skin.

The cosmetic ink composition can be delivered alone or in the presenceof a dermatologically-acceptable carrier. The phrase“dermatologically-acceptable carrier”, as used herein, means that thecarrier is suitable for topical application to a keratinous tissue, hasgood aesthetic properties, is compatible with any additional componentsof the cosmetic ink composition, and/or will not cause any untowardsafety or toxicity concerns. In one aspect, the cosmetic ink compositionis safe for use on skin. In one aspect, the cosmetic ink compositiondoes not comprise alkyds, celluloses, formaldehydes, phenolics, ketones,rubber resins, and combinations thereof because such ingredients may notbe compatible with use on human skin. In one aspect, the cosmetic inkcomposition can be hypoallergenic. Water is by far the most commoncarrier, and is typically used in combination with other carriers. Thecarrier can be in a wide variety of forms. Non-limiting examples includesimple solutions (water or oil based) or emulsions. The dermatologicallyacceptable carrier can be in the form of an emulsion. Emulsion may begenerally classified as having a continuous aqueous phase (e.g.,oil-in-water and water-in-oil-in-water) or a continuous oil phase (e.g.,water-in-oil and oil-in-water-in-oil). The oil phase may comprisesilicone oils, non-silicone oils such as hydrocarbon oils, esters,ethers, and the like, and mixtures thereof. For example, emulsioncarriers can include, but are not limited to, continuous water phaseemulsions such as silicone-in-water, oil-in-water, andwater-in-oil-in-water emulsion and continuous oil phase emulsions suchas water-in-oil and water-in-silicone emulsions, andoil-in-water-in-silicone emulsions.

The cosmetic ink composition can comprise water, preferably deionizedwater. The cosmetic ink composition can comprise from about 40% to about75% water, by weight of the cosmetic ink composition, alternatively fromabout 55% to about 70%, alternatively from about 60% to about 68%.

Additionally, the cosmetic ink composition can optionally includeanti-fungal and/or anti-bacterial components. Examples of anti-fungaland/or anti-bacterial components can include isothiazolinone such asmethylisothiazolinone and methylchloroisothiazolinone.

The cosmetic ink composition may comprise a safe and effective amount ofone or more skin care actives (“active”) useful for regulating and/orimproving the skin. “Safe and effective amount” means an amount of acompound or composition sufficient to induce a positive benefit but lowenough to avoid serious side effects (i.e., provides a reasonablebenefit to risk ratio within the judgment of a skilled artisan). A safeand effective amount of an active can be from about 1×10⁻⁶ to about 25%,alternatively from about 0.0001 to about 20%, alternatively from about0.01 to about 10%, alternatively from about 0.1 to about 5%,alternatively from about 0.2 to about 2%, all by weight of the cosmeticink composition.

Suitable skin care actives include, but are not limited to, vitamins(e.g., B3 compounds such as niacinamide, niacinnicotinic acid, andtocopheryl nicotinate; B5 compounds such as panthenol; vitamin Acompounds and natural and/or synthetic analogs of Vitamin A, includingretinoids, retinol, retinyl acetate, retinyl palmitate, retinoic acid,retinaldehyde, retinyl propionate, and carotenoids (pro-vitamin A);vitamin E compounds, or tocopherol, including tocopherol sorbate andtocopherol acetate; vitamin C compounds, including ascorbate, ascorbylesters of fatty acids, and ascorbic acid derivatives such as magnesiumascorbyl phosphate and sodium ascorbyl phosphate; ascorbyl glucoside;and ascorbyl sorbate); peptides (e.g., peptides containing ten or feweramino acids, their derivatives, isomers, and complexes with otherspecies such as metal ions); sugar amines (e.g., N-acetyl-glucosamine);sunscreens; oil control agents; tanning actives; anti-acne actives;desquamation actives; anti-cellulite actives; chelating agents; skinlightening agents; flavonoids; protease inhibitors (e.g., hexamidine andderivatives); non-vitamin antioxidants and radical scavengers; salicylicacid; hair growth regulators; anti-wrinkle actives; anti-atrophyactives; minerals; phytosterols and/or plant hormones; tyrosinaseinhibitors; N-acyl amino acid compounds; inositol; moisturizers; plantextracts; and derivatives of any of the aforementioned actives; andcombinations thereof. The term “derivative” as used herein refers tostructures which are not shown but which one skilled in the art wouldunderstand are variations of the basic compound. For example, removing ahydrogen atom from benzene and replacing it with a methyl group.

In one aspect, the cosmetic ink composition can comprise peroxide,including hydrogen peroxide and/or benzoyl peroxide.

In one aspect, the cosmetic ink composition can comprise a skin careactive selected from the group consisting of niacinamide, inositol, andcombinations thereof.

In one aspect, the cosmetic ink composition is substantially free oflatex polymer binders and/or a film forming polymers. In one aspect, thecosmetic ink composition comprises less than about 10% latex polymerbinders and/or film forming polymers, alternatively less than about 1%,alternatively less than about 0.1%. Without being limited by theory, itis believed that latex polymer binders and/or film forming polymers canmake printing difficult because these polymers can solidify afterevaporation and irreversibly plug the nozzles.

In one aspect, the cosmetic ink composition can comprise from about 10%to about 30% solids. In one aspect, the cosmetic ink compositioncomprises less than 40% solids. Without being limited by theory, it isbelieved that at a solids level of greater than 40%, such as inprepaints or paints, printing can be difficult because a high level ofsolids may lead to irreversible nozzle clogging.

In one aspect, the cosmetic ink composition can be removeable withwater, alternatively with soap and water.

Personal Care Device

In one aspect, the cosmetic ink composition described herein can beapplied to the skin using a hand-held personal care device. An exemplarypersonal care device can analyze the skin, identify skin imperfections,and deposit the cosmetic ink composition onto the identified skinimperfection in order to hide and/or camouflage the skin imperfection.

In one aspect, the personal care device can comprise a sensor configuredto take at least one image of skin and a processor configured tocalculate the average background lightness value of the image on a greyscale (lightness value on a grey scale is herein referred to as “Lvalue”). Further, from the same image, a local L value can be calculatedfor individual pixels or a group of pixels. The processor can thencompare the local L value to the background L value to identify skinimperfections. When a skin imperfection is identified, the processor canactivate one or more nozzles to fire and dispense the cosmetic inkcomposition onto the skin imperfection.

A skin imperfection is an area of skin where the absolute value of thedifference between a local L value and the background L, this differencebeing defined as the measured delta L (“ΔL_(M)”), is greater than apredetermined set delta L (“ΔL_(S)”). The background L can be preset orcalculated anywhere within the image. The image can be taken where thenozzles will fire the cosmetic ink composition. The background L can bethe arithmetic average, median, or mean of a plurality of local Ls,which means the calculation can include all of the local Ls in theimage, or a subset thereof.

FIG. 1, shows an exploded view of personal care device 40. Physicalspacer 42 of personal care device 40 is directly above skin surface 18.Physical spacer 42 has a set, predetermined height α such that when itcontacts skin surface 18, the mechanical and electrical elements are allat a known distance from skin surface 18. In one aspect, the height α isfrom about 1 mm to about 20 mm, alternatively from about 3 mm to about15 mm, alternatively from about 4 mm to about 10 mm.

The mechanical and electrical elements associated with personal caredevice 40 can include, but are not be limited to, light 44, sensor 46,nozzle array 20 which is embedded on cartridge die 57 which is attachedto cartridge 52. Cartridge die 57 can be made of silicon, glass,machinable glass ceramic, sapphire, alumina, printed wiring boardsubstrates (for example, Liquid Crystal Polymer, polyimide etc.) withinwhich nozzle array 20 can be formed. Nozzle array 20 can be in a linearconfiguration, multiple rows, off-set, sine wave, curved, circular, sawtooth arrangements, and combinations thereof. All of these elements canbe enclosed within optional apparatus housing 41.

Light 44 can illuminate the area of skin surface 18 within physicalspacer 42 such that sensor 46 has relatively constant illumination.Background lighting can affect sensor 46 as portions of physical spacer42 lift off skin surface 18 and allow background light in and theillumination from light 44 to escape. Small deviations in illuminationcan be corrected for provided light 44 provides a relatively constantbackground illumination. In one aspect, physical spacer 42 can beopaque. Light 44 can be a LED, incandescent light, neon bulb based, orany other commercially available source of illumination. Light 44 canhave constant illumination or adjustable illumination. For example, anadjustable light source might be useful if the background illuminationis excessively bright or dark.

Sensor 46 can be any component that is capable of obtaining a visualproperty of an area of skin surface. Non-limiting examples of sensorscan include optical sensors, image capture devices, spectrophotometers,photonic measuring devices for wavelengths within the visible spectrumas well as those wavelengths above and below the visible spectrum whichcould measure sub-surface features, and combinations thereof. The imagecapture device can be any of a variety of commercially available devicessuch as a simple camera or a digital cmos camera chip. In one aspect,the image capture device can be a camera and the images can be taken orconverted to a standard grey scale that is known in the art. It isunderstood that any numerical scale that measures lightness to darknesscan be considered a “grey scale”. Moreover, as used herein, “grey scale”is intended to be a linear scale, or one band, or one visual attribute.For example, one “grey scale” visual attribute could be singlewavelength or a narrow wavelength to define a specific visual color.Another example of one “grey scale” visual attribute could be a mix ofwavelength numerical values averaged for each pixel making up the image,such as a true black, grey or white image from an RGB mixture.

Sensor 46 can take a measurement of the L value of skin surface 18and/or an image of skin surface 18 and can send it to processor 50 viaimage capture line 48 for analysis. The image may be analyzed for localL values, background L values, or both. Grey scale conversion can occurwithin the analytical processing capabilities of processor 50. Thecomparison of background L to local L to determine the ΔL_(M) occurswithin processor 50, which can be a commercially available programmablechip, or other commercially available processing units.

Processor 50 is generally referred to as a central processing unit(“CPU”). The CPU can be a single programmable chip like those found inconsumer electronic devices such as a laptop computer, a cell phone, anelectric razor, and the like. The CPU may comprise an ApplicationSpecific Integrated Circuit (ASIC), controller, Field Programmable GateArray (FPGA), integrated circuit, microcontroller, microprocessor,processor, and the like. The CPU may also comprise memory functionality,either internal to the CPU as cache memory, for example Random AccessMemory (RAM), Static Random Access Memory (SRAM), and the like, orexternal to the CPU, for example as Dynamic Random-Access Memory (DRAM),Read Only Memory (ROM), Static RAM, Flash Memory (e.g., Compact Flash orSmartMedia cards), disk drives, Solid State Disk Drives (SSD), orInternet Cloud storage. While it is anticipated that a remote CPU,either tethered to the personal care device or which communicateswirelessly, can be used, a local CPU within the personal care device isexemplified herein.

Images can be taken in sequence or preferably continuously. The imagecapture device can take images at a speed of at least 4 frames persecond, alternatively at least 100 frames per second, alternatively atleast 200 frames per second, alternatively at least 600 frames persecond.

The CPU can process at a rate of 100 frames per second, alternativelygreater than 200 frames per second, alternatively greater than 600frames per second.

The results of the image analysis, when compared to criteriapre-programmed into processor 50, may result in a desired treatment ofskin surface 18. For instance, when the calculated ΔL_(M) exceeds thepre-determined ΔL_(S), a signal is sent from processor 50 to cartridge52, via cartridge line 51, to fire one or more nozzles 21 in nozzlearray 20 and dispense the cosmetic ink composition.

Power for cartridge 52, light 44, sensor 46, processor 50, and othermechanical and electrical elements that might be present can be suppliedby power element 54 via one or more power lines 55. Power element 54 canbe turned off and on, which in turn turns personal care device 40 offand on, via power switch 56 which can be located anywhere on personalcare device 40, but is shown here on device cover 58. Power element 54may include energy storage functionality via a battery, a rechargeablebattery, an electrochemical capacitor, a double-layer capacitor, asupercapacitor, a hybrid battery-capacitor system, and combinationsthereof.

FIG. 2 shows an exploded view of cartridge 52 comprising cartridge cap62 and cartridge body 64. Cartridge body 64 can include standpipe 66which is typically enclosed within cartridge body 64 and defines nozzleoutlet 68. Optional filter 70 can help keep excessively large particles,and other debris out of nozzle array 20. Filter 70 and nozzle array 20can be on opposite sides of nozzle outlet 68. Cosmetic ink composition74 can be contained within cartridge body 64. Foam core 72 can at leastpartially fill cartridge 64 and helps to regulate back pressure ofcosmetic ink composition 74. Back pressure can be regulated via bladders(not shown) and other methods known to the art. Foam core 72 shown hereis just one example of how to help regulate the flow of the cosmetic inkcomposition 74 to standpipe 66 through filter 70 and into nozzle array20. Connector 78 can provide the electrical power and signal to nozzlearray 20. Cosmetic ink composition 74 may be ejected from the cartridge52 by piezoelectric means, thermal means, mechanical pumping means, or acombination of these.

An exemplary cartridge for use herein can include cartridges describedin Patent Application US 2002/0167566.

There is no technical difference between an image used for background Lvalues and those used for local L values, the difference is in theanalysis of the image. Hence, the images are continually sent to theprocessor to calculate the L values and ΔL_(M) values. By “sent” it isunderstood, that preferably at least 4 bits of data per pixel aretransferred for each image, and preferably, this 4-bit (or more) packetof data is used in the calculation of each local L value.

It is understood, that the background L can be calculated once in atreatment period and that value can be reused throughout the treatmentperiod. Alternatively, it can be continually recalculated as long as thetreatment process goes on. Moreover, there can be pre-programmedtriggers to initiate a recalculation of the background L. Also, thebackground L may be retrieved from the processor memory to be used forthe current background L.

When the ΔL_(M) exceeds the predetermined value, the cosmetic inkcomposition can be deposited onto at least a portion of the skinimperfection. In particular, the cosmetic ink composition can bedeposited via an array of nozzles and the local L can be calculatedalong the length of, and in the firing range of, the array of nozzles.An individual nozzle may be fired to deposit the cosmetic inkcomposition, or multiple nozzles can be fired at the same time. Thenumber of nozzles fired along the array of nozzles can be adjusted basedon the size of the ΔL_(M) and the size of the skin imperfection.Furthermore, the frequency of nozzle firing can be adjusted based on theΔL_(M), with more droplets being fired in succession in response tolarger ΔL_(M) values.

The personal care device may deposit the cosmetic ink composition indroplets having an average diameter of from about from about 0.1 μm toabout 60 μm, alternatively from about 1 μm to about 50 μm, alternativelyfrom about 5 μm to about 40 μm. Preferably, the cosmetic ink compositioncan be applied to the skin imperfection in a discontinuous pattern ofdiscrete droplets.

The cosmetic ink composition can be printed from a cartridge having amicro-electro-mechanical system (MEMS) that is different from typicalconsumer printing applications. It is known that the typical chamberheight and nozzle plate thicknesses are from about 25 to about 50 μmsince typical printing inks have a viscosity of less than about 10 cP.In one aspect, the cartridge can comprise a chamber height and nozzleplate thicknesses of from about 10 to about 20 μm, preferably from about12 to about 17 μm. Without being limited by theory it is believed thatthe shorter chamber height and plate thickness can help minimize viscousloss. In addition, most consumer printing applications are optimized forprinting at 10 kHz or more, so ink formulas and microfluidics aredesigned to achieve rapid refill. However, operating the cosmetic inkcomposition described herein at this frequency range can result instreaming and/or de-priming due to gulping of air.

The cosmetic ink composition can be printed using the following start-upsequence: heating the substrate to about 60° C. for less than about 600ms, firing the nozzles in a burst of from about 100 to about 500 firesat a frequency of about 300 to about 1000 Hz, and then maintaining thelow shear condition with continuous 4 Hz firing. While it is possiblethe nozzles will start up with different algorithms, it is likely thatthe cosmetic ink composition would not be transitioned from its viscousat-rest state to a flowing state.

Also described herein is a method for depositing the cosmetic inkcomposition onto skin. The method for depositing a cosmetic inkcomposition onto skin can comprise the steps of:

-   -   a. providing a personal care device comprising one or more        nozzles and a cartridge operatively associated with the one or        more nozzles, wherein a cosmetic ink composition is disposed        within the cartridge; and    -   b. depositing the cosmetic ink composition onto a portion of        skin, wherein the cosmetic ink composition is deposited in a        discontinuous droplet pattern.

More specifically, a method for depositing a cosmetic ink compositiononto skin can comprise the steps of:

-   -   a. providing a personal care device comprising an array of        nozzles;    -   b. providing a background lightness (L) value;    -   c. obtaining a treatment image of skin and calculating at least        one local L value of individual pixels or group of pixels within        the treatment image;    -   d. comparing the local L value to the background L value;    -   e. identifying a skin deviation where the absolute value of the        difference between the local L value and the background L value        is greater than a predetermined set delta L value; and treating        the skin deviation with a cosmetic ink composition;        wherein the ink composition comprises a particulate material        having a Particle Size Distribution D50 of about 100 nm to about        2,000 nm; a polymeric dispersant, preferably having a weight        average molecular weight of less than about 5,000 daltons; a        rheology modifier, wherein the rheology modifier is selected        from the group consisting of alkali swellable emulsion polymers,        hydrophobically modified alkali swellable emulsion polymers, and        combinations thereof, and a surface tension modifier, wherein        the surface tension modifier is selected from the group        consisting of C1-C16 alcohols, C5-C18 diols, and mixtures        thereof.

EXAMPLES AND DATA

The following data and examples, including comparative examples, areprovided to help illustrate cosmetic ink compositions described herein.The exemplified compositions are given solely for the purpose ofillustration and are not to be construed as limitations of the presentinvention, as many variations thereof are possible without departingfrom the spirit and scope of the invention. All parts, percentages, andratios herein are by weight unless otherwise specified.

Surface Tension Study

Formulas were prepared to assess the impact of surface tension modifierson the surface tension and stability of the cosmetic ink composition.Examples 1-6 were made according to the procedure described hereafter.Example 1 is a control containing no surface tension modifier. Examples2, 3, and 4 illustrate a cosmetic ink composition containing the surfacetension modifier 1,2-Hexanediol/1,2-Octanediol, ethanol, and farnesol,respectively. Examples 5 and 6 are comparative examples containing aC12/C14 amine oxide or undecylenoyl phenylalanine, respectively, as thesurface tension modifier.

Examples 1-6 were made according to the following formulas. Weightpercent is shown as added.

TABLE 1 Control 1 2 3 4 5 6 Phase Description wt % wt % wt % wt % wt %wt % A 75 wt % TiO₂ 15.82 15.82 15.82 15.82 15.82 15.82 Slurry(WPG75PFSP)¹ A 45 wt % Iron 2.31 2.31 2.31 2.31 2.31 2.31 Oxide Slurry(WPG45GYSP)¹ A 45 wt % Iron 0.20 0.20 0.20 0.20 0.20 0.20 Oxide SlurryWPG45SIRSP)¹ B Deionized Water 48.07 47.07 43.07 47.57 45.27 49.07 BPuraGuard ™ 23.00 23.00 23.00 23.00 23.00 23.00 Propylene Glycol² BNiacinamide³ 5.00 5.00 5.00 5.00 5.00 0 B 5 wt % Darvan ® 2.60 2.60 2.602.60 2.60 2.60 811D⁴ in water B 15 wt % 3.00 3.00 3.00 3.00 3.00 3.00ACULYN ™ Excel⁵ in water C Symdiol ® 68⁶ 0 1.00 0 0 0 0 C Ethanol⁷ 0 05.00 0 0 0 C Farnesol⁸ 0 0 0 0.50 0 0 C C12/C14 0 0 0 0 2.80 0 AmineOxide⁹ C 5 wt % 0 0 0 0 0 4.00 Undecylenoyl Phenylalanine¹⁰ ¹Supplied byKOBO Products Inc (South Plainfield, NJ). ²Available from The DowChemical Company (Lake Zurich, IL). ³Available from VertellusAgriculture & Nutrition (Indianapolis, IN). ⁴Available from AshlandSpecialty Chemical (Wilmington, DE). ⁵Polyacrylate available from TheDow Chemical Company (Lake Zurich, IL). ⁶1,2-Hexanediol, 1,2-Octanediolavailable from Symrise AG (Branchburg, NJ). ⁷Available from AaperAlcohol & Chemical Co (Shelbyville, KY). ⁸Available from Symrise AG(Branchburg, NJ). ⁹Available from P&G (Kansas City, KS). ¹⁰A 5 wt %mixture of undecylenoyl phenylalanine (available from Seppic, Fairfield,NJ) was made by adding undecylenoyl phenylalanine to DI water andadjusting the pH to >7 with AMP-Ultra ® PC 2000 (available from AngusChemical, Buffalo Grove, IL).

The surface tension and rheology were measured initially and thensamples were stored in sealed glass jars at 50° C. until stabilitymeasurements were performed. The table below shows the surface tension,viscosity, G′, G″, tan(delta), and separation for each example.Viscosity was measured according to the Viscosity Test Method describedhereafter. Tan(delta) was calculated by using the storage modulus andloss modulus measured according to the Oscillatory Strain Sweep Methoddescribed hereafter. Separation was measured according to the SeparationTest Method described hereafter. Separation is recorded in Table 2 asthe mm of separation after 15 days at 50° C.

TABLE 2 Surface Separation Tension (mm Surface Modifier SurfaceViscosity Viscosity separation Tension wt % Tension (cP, (cP, tan at 15days, Ex Modifier (active) (mN/m) 0.1 s⁻¹) 1000 s⁻¹) G′ G″ (delta) 50°C.) 1 None 0 50.0 3180 43 4.53 2.09 0.46 0 (Control) 2 Symdiol ® 68 1.0040.0 3130 44 4.26 2.05 0.48 0 3 Ethanol 5.00 45.4 3920 52 5.16 2.51 0.480 4 Farnesol 0.50 39.0 3480 50 5.40 2.78 0.52 0 5 C12/C14 0.145 37.72410 44 3.50 1.77 0.51 1.8 Amine Oxide 6 Undecylenoyl 0.20 42.0 1600 281.67 1.07 0.64 25.7 Phenylalanine

It was surprisingly found that some surface tension modifiers, whileable to lower the surface tension of the cosmetic ink composition,disrupted stability by lowering the viscosity such that significantseparation occurred, demonstrating the insufficient internal structureto suspend the particles. Without being bound by theory, it is believedthat humectants like propylene glycol are too hydrophilic tosufficiently reduce surface tension.

Example 1 (Control), which contained no surface tension modifier, had asurface tension of 50 mN/m. Although Example 1 was able to build aviscosity sufficient to suspend the particles, it is believed that acosmetic ink composition having a surface tension of 50 mN/m may not beable to wet a wide range of skin types and consequently print durabilityand/or coverage will be poor. It is desirable to have a surface tensionof less than about 45 mN/m while maintaining a viscosity such thatstability is maximized without the need for agitation.

When Symdiol® 68 (Example 2), a C8 diol, and farnesol, a C15 alcohol,(Example 4) were added, the surface tension of the sample decreased to40 mN/m or less while the viscosity increased as compared to thecontrol. In addition, the tan(delta) of Examples 2 and 4 were 0.48 and0.52, respectively, demonstrating the viscoelastic properties weresuitable for printing.

When ethanol, a C2 alcohol, was added (Example 3), the surface tensionof the sample decreased to 45.4 mN/m while the viscosity increased ascompared to control. In addition, the tan(delta) of Example 3 was 0.48,demonstrating the viscoelastic properties were suitable for printing.Because of the volatility of ethanol, it is believed the surface tensionmay increase over time.

When a C12/C14 amine oxide was added (Example 5), the surface tensiondecreased to 37.7 mN/m, however, the viscosity also decreased ascompared to control. Similarly, when undecylenoyl phenylalanine wasadded (Example 6), the surface tension decreased to 42.0 mN/m, but theviscosity also decreased as compared to control. Not wishing to be boundby theory, it is believed that the C12/C14 amine oxide and undecylenoylphenylalanine disrupted the weak colloidal gel structure of the cosmeticink composition, resulting in the decrease in viscosity. In addition,Examples 6 had a tan(delta) of 0.64 and a high level of separation at50° C. was observed.

Examples 1-6 were made according to the following procedure.

First, the ingredients of Phase A were combined in an appropriate premixcontainer and mixed for 30 minutes. The ingredients of Phase B wereadded into a main container. Phase B was mixed using a mixer with apropeller blade, such as a digital Eurostar 400® available from IKA®(Staufen im Breisgau, Germany) or equivalent, at low speed until themixture was homogenous. The pH of the Phase B mixture was measured.Then, the contents of the premix container were transferred into themain container and mixed for 30 minutes. Approximately 10% of the waterwas withheld from Phase B and was used to wash the premix container andthen added to the main container while mixing. Phase C was added to themain container. The mixing speed was increased to high speed and mixingcontinued for 10 minutes. Phase D was then added dropwise to the maincontainer and the pH was maintained between 7.5-8.5 by adding 20% KOH.Homogeneity was ensured and the mixture was poured into a container,labeled, and stored at ambient conditions before use.

Surface Tension Method

Surface tension is measured according to ASTM 1331-14 (Published January2015) using an EZ-Pi tensiometer (Kibron, Parrish, Fla.), or equivalent.The instrument is calibrated according to the manufacturer instructionsusing DI water. Measurements are taken and values are reported in mN/m.

Viscosity Test Method

Viscosity is measured using a rheometer as a function of shear rate. Asuitable rheometer can include an Ares M (available from TA Instruments,New Castle, Del.), or equivalent. First, the samples and standards areequilibrated at room temperature prior to analysis. A 50 mm, 2 degree,cone and plate is zeroed prior to testing. While the sample is at 25°C.±0.5° C., the sample is tested. A shear sweep measurement is performedover a range of 0.1-1000 s⁻¹ to determine the shear thinning propertiesand viscosity at different shear rates.

Oscillatory Strain Sweep Method

Oscillatory strain sweep is measured using a rheometer (such as anARES-G2 available from TA Instruments, New Castle, Del.), or equivalent.

The samples and standards are allowed to equilibrate at ambientconditions prior to analysis. The rheometer is calibrated as disclosedin the operator's manual. The oscillatory strain sweep measurement isperformed at a fixed angular frequency of 6.28 rad/s over a strain rangeof 0.0001-1 using a 40 mm 316SST (APS heat break) parallel plate at 25°C., with a 0.05 mm gap, to determine the storage and loss moduli.

Particle Size Distribution Method

The particle size distribution is determined using a laser scatteringparticle size distribution analyzer. A suitable laser scatteringparticle size distribution analyzer can include a Horiba LA-950V2(available from Horiba, Ltd., Kyoto, Japan). In this method, theprinciples of Mie and Fraunhofer scattering theories are used tocalculate the size and distribution of particles suspended in a liquid.Results are normally displayed on a volume basis. The application ofthis method to pigments has been developed using a flow cell procedure.

Samples are prepared by vortexing for 30 seconds with a Vortex Genie 2to ensure there is no residue in the bottom of the sample vial. 200 mLof deionized (DI) water is added into the instrument reservoir andanalyzed as a blank sample. A disposable micro pipet is used to dispenseenough sample into the DI water in the instrument until theTransmittance is reduced from 100 down to 90±2%, approximately 250 μL.Results are reported as D50 or D90.

Particle Settling Test Method

Particle settling is measured as follows. An aluminum dish is weighed todetermine the dish weight. A 1 gram aliquot of the sample from the top,middle, or bottom of the sample vial is added to the dish and weighed todetermine the wet weight. “Top” means the surface of the sample in thevial. “Middle” means the middle of the vial. “Bottom” means the bottomof the vial. The dish with the sample aliquot is placed in an oven at100° C. for one hour to evaporate the volatiles. The dish is removed andweighed again to get a dry weight. The weight % solids is calculated bythe following equation: (dry weight−dish weight)/(wet weight−dishweight).

Zeta Potential Test Method

Zeta potential is measured using a Zeta potential analyzer such as aNanoBrook ZetaPALS Potential Analyzer available from BrookhavenInstruments Corporation, Holtsville, N.Y., or equivalent.

Zeta potential test samples are prepared by diluting the sample to 0.1g/ml into deionized water. Zeta potential is measured on a Zetapotential analyzer using the Smoluchowski Zeta potential model with 5runs and 10 cycles. After running a standard (BIZR3), the cells of theZeta potential analyzer are loaded with 1 ml of test sample. Zetapotential is measured as a function of pH.

Separation Test Method

Separation is measured by filing an 8-dram (1 oz., 25 mm×95 mm) screwcap glass vial to a height of 55 mm with the sample composition (asmeasured from the bottom of the vial to the top of the liquidcomposition). The vials are sealed and are placed in controlledtemperature chambers. The vials are held in static storage untilmeasurements are performed. At each time point, the vial is carefullyremoved from the chamber without vigorous or prolonged agitation andobserved for any visual signs of separation and the type of separationis noted as syneresis or settling. The amount of separation isdetermined by measuring the mm of clear fluid at the top of the samplewith a digital caliper.

Combinations

-   -   A. A cosmetic ink composition comprising: from 1 to 45 active wt        % of a particulate material having a Particle Size Distribution        D50 of 100 nm to 2,000 nm; a rheology modifier, wherein the        rheology modifier is selected from the group consisting of an        alkali swellable emulsion polymer, a hydrophobically modified        alkali swellable emulsion polymer, and combinations thereof; a        polymeric dispersant; and a surface tension modifier selected        from the group consisting of C1-C16 alcohols, C5-C18 diols, and        mixtures thereof.    -   B. The cosmetic ink composition of paragraph A, wherein the        surface tension modifier is selected from the group consisting        of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol,        2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, farnesol,        benzyl alcohol, phenyl ethyl alcohol, phenoxyethanol,        2-phenylphenol, methyl 4-hydroxybenzoate, ethyl        4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl        4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, chloroxylenol,        2-methyl 5-cyclohexypentanol, triclosan, 1,2-pentanediol,        1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol,        1,2-octanediol, 1,8-octanediol, 2-methyl 5-cyclohexypentanol,        1,2-decanediol, 3-[(2-ethylhexyl)oxy]-1,2-propanediol, and        mixtures thereof.    -   C. The cosmetic ink composition of paragraph A, wherein the        surface tension modifier is selected from the group consisting        of 1,2-hexanediol, 1,2-octanediol, ethanol, farnesol, and        mixtures thereof.    -   D. The cosmetic ink composition of any of the preceding        paragraphs, wherein the cosmetic ink composition has a        tan(delta) of less than 0.60, preferably less than 0.55, even        more preferably less than 0.50.    -   E. The cosmetic ink composition of any of the preceding        paragraphs wherein the polymeric dispersant has a weight average        molecular weight of less than 5,000 daltons, preferably from        2,000 to 5,000 daltons, more preferably from 2,500 to 4,000        daltons.    -   F. The cosmetic ink composition of any of the preceding        paragraphs wherein the cosmetic ink composition comprises        greater than 0.30 active wt % rheology modifier.    -   G. The cosmetic ink composition of any of the preceding        paragraphs comprising from 0.1 to 5 active wt % of the surface        tension modifier, preferably from 0.5 to 3 active wt %, more        preferably 1 to 2 active wt %.    -   H. The cosmetic ink composition of any of the preceding        paragraphs wherein the particulate material has a Particle Size        Distribution D50 of from 150 nm to 1,000 nm, preferably from 200        nm to 450 nm, most preferably from 200 nm to 350 nm.    -   I. The cosmetic ink composition of any of the preceding        paragraphs wherein the particulate material has a Particle Size        Distribution D90 of from 700 nm to 900 nm.    -   J. The cosmetic ink composition of any of the preceding        paragraphs wherein the particulate material is selected from the        group consisting of a pigment, a metal oxide, a colorant, a dye,        a clay, and combinations thereof.    -   K. The cosmetic ink composition of any of the preceding        paragraphs wherein the rheology modifier is an alkali swellable        acrylic polymer emulsion.    -   L. The cosmetic ink composition of any of the preceding        paragraphs, wherein the cosmetic ink composition has a surface        tension of from 20 mN/m to 45 mN/m, preferably from 30 mN/m to        40 mN/m.    -   M. The cosmetic ink composition of paragraph any of the        preceding paragraphs, further comprising one or more skin care        actives selected from the group consisting of niacinamide,        inositol, and combinations thereof.    -   N. The cosmetic ink composition of any of the preceding        paragraphs, further comprising from 20 to 30 active wt % of a        humectant.    -   O. The cosmetic ink composition of any of the preceding        paragraphs, wherein the cosmetic ink composition has a first        dynamic viscosity of 1,100 cP to 10,000 cP at a shear rate of        0.1 sec⁻¹ measured at 25° C., preferably 1,500 cP to 8,000 cP,        more preferably from 2,000 cP to 5,000 cP, and a second dynamic        viscosity of from 10 to 100 cP at a shear rate of 1,000 sec⁻¹        measured at 25° C., preferably from 20 to 80 cP.    -   P. The cosmetic ink composition of any of the preceding        paragraphs wherein the cosmetic ink composition has a neat pH of        from 7.5 to 9.0.

Values disclosed herein as ends of ranges are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each numerical range is intended to meanboth the recited values and any integers within the range. For example,a range disclosed as “1 to 10” is intended to mean “1, 2, 3, 4, 5, 6, 7,8, 9, and 10.”

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A cosmetic ink composition comprising: a. fromabout 1 to about 45 active wt % of a particulate material; b. greaterthan about 0.30 active wt % of a rheology modifier, wherein the rheologymodifier is selected from the group consisting of a (meth)acrylatepolymer, a (meth)acrylate copolymer, and mixtures thereof; c. from about0.01 to about 1 active wt % of a polymeric dispersant; d. from about 0.1to about 5 active wt % of a surface tension modifier, wherein thesurface tension modifier is selected from the group consisting of C1-C16alcohols, C5-C18 diols, and mixtures thereof; and e. from about 10 toabout 30 active wt % of a humectant.
 2. The cosmetic ink composition ofclaim 1 wherein the cosmetic ink composition has a surface tension offrom about 20 mN/m to about 45 mN/m.
 3. The cosmetic ink composition ofclaim 1 wherein the surface tension modifier is a C6-C12 diol or a C15alcohol.
 4. The cosmetic ink composition of claim 1 wherein cosmetic inkcomposition has a first dynamic viscosity of greater than about 500 cPat a shear rate of 0.1 sec⁻¹ measured at 25° C. and a second dynamicviscosity of less than about 100 cP at a shear rate of 1,000 sec⁻¹measured at 25° C.
 5. The cosmetic ink composition of claim 1 whereinthe particulate material has a Particle Size Distribution D50 of about200 nm to about 350 nm.